/**
 * jQuery Templates
 *
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 *
 * Written by: Stan Lemon <stanlemon@mac.com>
 *
 * Based off of the Ext.Template library, available at:
 * http://www.extjs.com
 *
 * This library provides basic templating functionality, allowing for macro-based
 * templates within jQuery.
 *
 * Basic Usage:
 *
 * var t = $.template('<div id="foo">Hello ${name}, how are you ${question}?  I am ${me:substr(0,10)}</div>');
 *
 * $(selector).append( t , {
 *     name: 'Stan',
 *     question: 'feeling',
 *     me: 'doing quite well myself, thank you very much!'
 * });
 *
 * Requires: jQuery 1.2+
 *
 *
 * @todo    Add callbacks to the DOM manipulation methods, so that events can be bound
 *          to template nodes after creation.
 */
(function($){
	
	/**
	 * Create a New Template
	 */
	$.template = function(html, options) {
		return new $.template.instance(html, options);
	};

	/**
	 * Template constructor - Creates a new template instance.
	 *
	 * @param 	html 	The string of HTML to be used for the template.
	 * @param 	options An object of configurable options.  Currently
	 * 			you can toggle compile as a boolean value and set a custom
	 *          template regular expression on the property regx by
	 *          specifying the key of the regx to use from the regx object.
	 */
	$.template.instance = function(html, options) {
        // If a custom regular expression has been set, grab it from the regx object
        if ( options && options['regx'] ) options.regx = this.regx[ options.regx ];

		this.options = $.extend({
			compile: 		false,
			regx:           this.regx.standard
		}, options || {});

		this.html = html;

		if (this.options.compile) {
			this.compile();   
		}
		this.isTemplate = true;
	};

	/**
	 * Regular Expression for Finding Variables
	 *
	 * The default pattern looks for variables in JSP style, the form of: ${variable}
	 * There are also regular expressions available for ext-style variables and
	 * jTemplate style variables.
	 *
	 * You can add your own regular expressions for variable ussage by doing.
	 * $.extend({ $.template.re , {
	 *     myvartype: /...../g
	 * }
	 *
	 * Then when creating a template do:
	 * var t = $.template("<div>...</div>", { regx: 'myvartype' });
	 */
	$.template.regx = $.template.instance.prototype.regx = {
	    jsp:        /\$\{([\w-]+)(?:\:([\w\.]*)(?:\((.*?)?\))?)?\}/g,
        ext:        /\{([\w-]+)(?:\:([\w\.]*)(?:\((.*?)?\))?)?\}/g,
        jtemplates: /\{\{([\w-]+)(?:\:([\w\.]*)(?:\((.*?)?\))?)?\}\}/g
	};
	
	/**
	 * Set the standard regular expression to be used.
	 */
	$.template.regx.standard = $.template.regx.jsp;
	
	/**
	 * Variable Helper Methods
	 *
	 * This is a collection of methods which can be used within the variable syntax, ie:
	 * ${variable:substr(0,30)} Which would only print a substring, 30 characters in length
	 * begining at the first character for the variable named "variable".
	 *
	 * A basic substring helper is provided as an example of how you can define helpers.
	 * To add more helpers simply do:
	 * $.extend( $.template.helpers , {
	 *	 sampleHelper: function() { ... }	
	 * });
	 */
	$.template.helpers = $.template.instance.prototype.helpers = {
		substr : function(value, start, length){
			return String(value).substr(start, length);
		}
	};


	/**
	 * Template Instance Methods
	 */
	$.extend( $.template.instance.prototype, {
		
		/**
		 * Apply Values to a Template
		 *
		 * This is the macro-work horse of the library, it receives an object
		 * and the properties of that objects are assigned to the template, where
		 * the variables in the template represent keys within the object itself.
		 *
		 * @param 	values 	An object of properties mapped to template variables
		 */
		apply: function(values) {
			if (this.options.compile) {
				return this.compiled(values);
			} else {
				var tpl = this;
				var fm = this.helpers;

				var fn = function(m, name, format, args) {
					if (format) {
						if (format.substr(0, 5) == "this."){
							return tpl.call(format.substr(5), values[name], values);
						} else {
							if (args) {
								// quoted values are required for strings in compiled templates, 
								// but for non compiled we need to strip them
								// quoted reversed for jsmin
								var re = /^\s*['"](.*)["']\s*$/;
								args = args.split(',');

								for(var i = 0, len = args.length; i < len; i++) {
									args[i] = args[i].replace(re, "$1");
								}
								args = [values[name]].concat(args);
							} else {
								args = [values[name]];
							}

							return fm[format].apply(fm, args);
						}
					} else {
						return values[name] !== undefined ? values[name] : "";
					}
				};

				return this.html.replace(this.options.regx, fn);
			}
		},

		/**
		 * Compile a template for speedier usage
		 */
		compile: function() {
			var sep = $.browser.mozilla ? "+" : ",";
			var fm = this.helpers;

			var fn = function(m, name, format, args){
				if (format) {
					args = args ? ',' + args : "";

					if (format.substr(0, 5) != "this.") {
						format = "fm." + format + '(';
					} else {
						format = 'this.call("'+ format.substr(5) + '", ';
						args = ", values";
					}
				} else {
					args= ''; format = "(values['" + name + "'] == undefined ? '' : ";
				}
				return "'"+ sep + format + "values['" + name + "']" + args + ")"+sep+"'";
			};

			var body;

			if ($.browser.mozilla) {
				body = "this.compiled = function(values){ return '" +
					   this.html.replace(/\\/g, '\\\\').replace(/(\r\n|\n)/g, '\\n').replace(/'/g, "\\'").replace(this.options.regx, fn) +
						"';};";
			} else {
				body = ["this.compiled = function(values){ return ['"];
				body.push(this.html.replace(/\\/g, '\\\\').replace(/(\r\n|\n)/g, '\\n').replace(/'/g, "\\'").replace(this.options.regx, fn));
				body.push("'].join('');};");
				body = body.join('');
			}
			eval(body);
			return this;
		}
	});


	/**
	 * Save a reference in this local scope to the original methods which we're 
	 * going to overload.
	 **/
	var $_old = {
	    domManip: $.fn.domManip,
	    text: $.fn.text,
	    html: $.fn.html
	};

	/**
	 * Overwrite the domManip method so that we can use things like append() by passing a 
	 * template object and macro parameters.
	 */
	$.fn.domManip = function( args, table, reverse, callback ) {
		args = $.makeArray(args);

		if (args[0].isTemplate) {
			// Apply the template and it's arguments...
			args[0] = args[0].apply( args[1] );
			// Get rid of the arguements, we don't want to pass them on
			delete args[1];
		}

		// Call the original method
		var r = $_old.domManip.apply(this, arguments);

		return r;
	};

    /**
     * Overwrite the html() method
     */
	$.fn.html = function( value , o ) {
	    if (value && value.isTemplate) var value = value.apply( o );

		var r = $_old.html.apply(this, [value]);

		return r;
	};
	
	/**
	 * Overwrite the text() method
	 */
	$.fn.text = function( value , o ) {
	    if (value && value.isTemplate) var value = value.apply( o );

		var r = $_old.text.apply(this, [value]);

		return r;
	};

})(jQuery);
